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Yet more augen!
Here the augen are found not only low down in the stream bed, but also higher up at the roadside. They have also become more frequent. This change in elevation reflects the fact that as we progress further up the valley, we are deeper within the gneissic dome and further down in the sequence of strata

Close up of a group of three augens

A group of augen


gneiss without pronounced banding

a stretched lineation which may indicate that this rock has been subjected to shear
In some locations the foliation is stretched out, a rock texture which is formed by shear, a sliding movement which causes the crystals to be stretched and recrystallised into smaller flatter ones. The direction of the linear crystals lie in the direction of movement.
Augens by th roadside
A well known geologist introduces us to where we can see a well exposed rock face with many augen

Size, shape and orientation The augen occur both singly and in groups, as seen on the left. They range in size up to 12 cm x 8 cm. The long axis of the lozenge shape follows the direction of the compositional banding, which at this location is fairly planar, Elsewhere it is variously folded and a convoluted and disordered pattern.


Gen view of augenitic rock
Smaller and fewer augen here. This photo was taken quite close to the others on this page. This reflects the variability of the density of augen (porphyroblasts).

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